A serious problem exists in attempts to prevent water penetration into structures. In fact, as long as there have been structures, there has been a search for water prevention devices of all types. By way of example only and not by limitation, thru-wall flashings are used in buildings to prevent water penetrating through the interior wall of a cavity wall system. In concrete masonry unit (CMU) construction these flashings are installed at door heads, window heads and sills, and at the base of cavity walls. Flashing is also installed at floor lines in multi-story buildings and in curtain wall and storefront glazing systems.
For many years flashing materials were made from semi-rigid metal sheets, such as copper, galvanized steel, and aluminum. The metal flashings were installed in the CMU joints as coursing reached the point where they had to be installed to assure proper anchorage. The distance varies, but is usually sixteen inches above a finished floor line and eight inches above a door or window head. This approach left the exposed metal flashing material hanging down the face of the CMU and subject to physical damage and weather for long periods of time. Also, the vertical or lapped joints between sections of flashing had to be soldered or joined in some permanent, waterproof method, typically by a metal worker. While this system helped solve the problem of holding the flashing in place, this system added significant cost because it involved expensive materials that could be damaged easily, were difficult to replace properly, and required two different laborers to complete the work.
As a variety of plastics and rubber-based materials became available for flashings they were quickly substituted for the metal flashings to reduce costs. But the installation sequence remained unchanged so the materials were still hanging down the face of the wall subjecting the membrane to weather and physical damage and resulting in the flashing falling away from or totally off the structure until the veneer was applied.
Recently a system of self-adhering membranes and metal termination bars has become a popular flashing system. The self-adhering membrane is the primary flashing material and has one surface consisting of an adhesive that is temporarily protected by a paper coating. The coating is removed to expose the adhesive when installation begins. This material is commonly referred to as a “peel and stick” membrane. The membrane thickness varies but is generally in the forty mil range. The membrane is usually manufactured in rolls so that specific widths can be cut from the roll as wall height and cavity width conditions require.
With the self-adhering membrane, the flashing can be installed just before the outer veneer is to be applied which eliminates weather damage and significantly reduces physical damage prevalent in prior art systems. At the time of installation, a portion of the paper coating is removed and the top edge of the membrane is secured to the CMU wall by pressing the adhesive surface against the CMU. This membrane is fully adhered to the face of the wall starting, typically, a minimum of sixteen inches above the floor line (eight inches at a window or door head) and extending downward at least eight inches (one block). The remaining membrane section is loosely hung and curved away from the inner wall where it is terminated on top of the outer veneer at the outside edge.
The membrane adhesive alone, however, is not considered an adequate or long-term solution for holding the membrane to the wall. The membrane is subject to peeling back from the top and falling away from the CMU. Thus, installation of a termination bar at the top edge of the membrane is still required to provide long-term attachment. The termination bar is commonly fabricated in eight to ten foot long pieces of stainless steel or aluminum of varying thicknesses. Screws, made of similar materials, are installed in predrilled holes spaced anywhere from two to twelve inches on center along the centerline of the termination bar. To secure the bar it is necessary to either drill holes into the CMU using the pre-drilled holes in the bar as a guide, or use a power actuated fastener shot into the CMU through the holes. Once the bar is installed, a continuous bead of sealant is often applied along the top edge and at the drilled holes. This is done to prevent water that may penetrate the wall cavity from collecting on top of the bar and at the holes and eventually working through the mortar joint to the interior.
While the current membrane and termination bar system reduces potential damage to the flashing and does an adequate job of holding the flashing in place, it does not significantly reduce the cost of labor. And there is no certainty that the screws or other fasteners, and the sealant have been properly or completely installed. Once the veneer is applied and the wall cavity is enclosed it is impossible to detect and repair the source of the leak or reattach the membrane without removing the veneer.
What is required is a flashing attachment apparatus and method that is inexpensive, easy to use and that creates no new entries for water while ensuring that the flashing is held in place. It, therefore, is an object of this invention to provide a flashing attachment apparatus and method that requires no drilling, that once installed is held in place without screws or additional securing devices, that creates a stable termination bar that provides an overlapping attachment with flashing, and that is inexpensive to manufacture and easy to install.